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Pioneer SA9800

Robert

Robert

Tapehead
Managed to sort the broken voltage selector on what is otherwise a mint classic amp.

It sounds superb. Very clean, bags of power and times pretty well. Softer and warmer than the Linn amps I have but none of the brash 'transistor' sound that amps from the 70's can display.
The phono stage is a cracker. The input resistance can be set to 100/470/10k/25k/47k/100k and input capacitance between 100/200/300/400/500pf at the spin of 2 knobs.

One shock was seeing the power meter reveal that driving the Impulse H2s at what I'd class as very loud was using around 1 watt !!
My system therefore hovers around 0.2-0.5 watts most of the time. Christ I could probably drive them straight from the pre!
The electronics in the pioneer are so quiet that there is no hum and a very faint hiss from the tweeter/mid horn with my ear pressed right up close. Amazing for something 25 years old.

One small problem is that when 1st turned on the amp is dead for about 30 secs then the power supply slowly coughs and splutters it's way to life - just like a valve amp except there are no valves :confused:

Any ideas?
 
One small problem is that when 1st turned on the amp is dead for about 30 secs then the power supply slowly coughs and splutters it's way to life - just like a valve amp except there are no valves
Click to expand...

Do you measure this behaviour with a meter?

I'd look to everything from the mains switch to the smoothing caps for starters, to see if it provides a clue.

Are there any relays in there - could be a prime candidate, unless they have sow start-up by design.

I wonder if it has a protection circuit looking at DC at the output - it could be DC is too high at start and the amp disconnects the speakers (lots of old amps had relays in the output) - as it warms and DC offset falls they could switch?

A thought anyway.

Andy.
 
Hi Andy,

When switched on from cold the power-on indicator lights but the amp is dead with no sound. The blue power meters are also dead. After about 30 secs the meter starts to flicker dimly, slowly getting brighter until it suddenly bursts to full intensity. Monitoring the output while all this is going on shows a scratchy distorted sound getting louder until it suddenly bursts into life.

I've not measured DC offset. I'll try that. It is a DC coupled amp according to the blurb in the manual.
The relay seems to work fine. If I turn the amp off for an hour it starts fine. Leave it off for 24 hours+ and i get the problem.
Sounds great when working.

I believe the amp was stored for about 20 years in its original packing. It looks (and smells - yum;) like new. The packing was dry and the amp looks to have been well stored in the US.
 
Been using the pioneer for a few weeks now.

This amp sounds fantastic. Nothing like ít's image or the reputation of 70s/80s amps of this type would suggest.

Clean, controlled, powerful, bags of dynamics and pretty decent PRaT. The Phono stage is superb. Very quiet and transparent even on MC. Noise levels of -74db on MC gives the likes of the Linto lots to worry about - and this pioneer is 24 years old.

The only problem is that this amp trounces a Linn Wakonda/LK280X2 - which is a little worrying :confused:
 
<Sigh>

I used to have one, but a dry joint in the circuit somewhere steadfastly got worse and I found it easier to trade on to a new amp. The funny thing is I don't remember it sounding particularly good with an AR turntable and AR94 loudspeakers in tow. Perhaps mine had been thrashed at a party once too often. I also had the matching SG-9800 graphic equaliser.

James
 
funny thing is I don't remember it sounding particularly good
Click to expand...

I also find this hard to believe....but then its not my ears !

Rob, Correct me if I'm wrong,
you went from

Naim
to Exposure
to Linn
to Pioneer

eh...?
is it those horn speakers or am I missing something ?

Next time I'm passing a garage sale I'd better watch out for those pioneer things, one can never tell..

Enjoy
 
Hi Per,

"I also find this hard to believe....but then its not my ears ! "

Very true. But - open the pioneer and look at the circuits and components and there is no reason why it shouldn't compete with Linn/Naim/Rega/insert fav brand.



"Rob, Correct me if I'm wrong,
you went from

Naim
to Exposure
to Linn
to Pioneer

eh...?
is it those horn speakers or am I missing something ? "


Not quite -

Cyrus to Naim to Exposure to Linn to Pioneer.

Now everything is gone except the Pioneer which is for use in a seperate retro system anyway.

I currently have no CD player, Pre or power amps. I sold the lot and intend to spend a few months in quiet contemplation while I decide what direction my main system will go.

So much good kit - so many good points......and so many bad.
Guess I'm just a restless perfectionist :)

And yes it's all due to those horns. Utterly transparent and enthralling at times like nothing else, but ruthless at exposing source and amp problems.

In fact not only won't I be using my main system for a while but this is my last post here for a couple of months.

I need a complete break - :(
 
Is this a SDC coupled amp ? If so then the lag in start up will be while the power rails stabilise. Can you hear a relay clicking in at the time the amp appears to turn on?

If my assumption is correct ( DC coupled ) then I'd be looking to a tired power supply causing some stability issues. There are several things we can speculate on at this point.
 
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